Discovery of DNA Gyrase as a Promising Target against Phytopathogenic Bacteria

The growing resistance of phytopathogenic bacteria highlights
the
need for new bactericides. DNA gyrase, essential in bacteria but absent
in plants and animals, is an underexploited target for agricultural
bactericides. Here, we modeled the Ralstonia solanacearum GyrA–GyrB–DNA complex using AlphaFold3 and conducted
structure-based virtual screening of 1.27 million compounds. Among
100 tested candidates, GI-A14 showed potent, broad-spectrum antibacterial
activity against R. solanacearum, Pseudomonas syringae pv tomato, and Xanthomonas oryzae pv oryzae, with minimum inhibitory
concentrations of 1–4 μg/mL. Enzymatic assays confirmed
that GI-A14 stabilizes the gyrase–DNA cleavage complex, indicating
a DNA-interfacial inhibition mechanism. Furthermore, GI-A14 significantly
attenuated the pathogenicity and biofilm formation of R. solanacearum. In planta, GI-A14 provided strong
protection against bacterial wilt, speck, and blight, outperforming
the commercial agent zhongshengmycin. These results establish DNA
gyrase as a viable molecular target for plant disease control and
identify GI-A14 as a promising lead compound for next-generation green
bactericides.